1. Field of the Invention
The present invention relates to a lower cutter for a compact printer and a cutting device including the same, and more particularly to a lower cutter for a compact printer and a cutting device including the same, in which the lower cutter includes a cutting blade having a reduced area engaged to an upper cutter and is adapted to be elastically displaced, thereby preventing a jam phenomenon of a paper and reducing a size of a lower cutter.
2. Description of the Prior Art
In general, a compact printer is commonly used in printing a paper supplied from a rolled paper of a certain width to create a itemized receipt etc. in a dot printing manner or an ink-jet printing manner and issuing the printed itemized receipt etc.
Such compact printers can be classified into a scissors type, a guillotine type and a rotary type according to a shape of a cutter.
FIG. 1 shows a conventional compact printer in perspective, in which a shutter member is opened. As shown in the drawing, a conventional compact printer 1 includes an upper cutter disposed at a clamshell-shaped cover 1—1, and a lower cutter disposed at a printer body 102. The upper cutter 10 is laterally operated from a side of a printed paper to an opposite side to sever the printed paper “P” discharged from the printer body 1-2 while being in close contact with the lower cutters 20.
FIGS. 2 and 3 are cross-sectional views showing the relation of an upper cutter and a lower cutter of the conventional compact printer. As shown in the drawings, the upper cutter 10 is a rotary type auto cutter, which is adapted to be rotated by drive means and supported by a carriage 3. The carriage 3 is provided at its side with a driving gear coupled to an end of a rotating shaft “H”. The rotating shaft “H” is coupled at the other end to the upper cutter of a certain diameter. The rotating shaft “H” is also provided between the carriage 3 and the upper cutter 10 with elastic means “S” inserted thereon.
The carriage 3 is housed in a case 4. The case 4 is provided at its front and upper portion with a shutter member 5, which is rotatably supported at one end by a hinge pin “h”.
The shutter member 5 is adapted to shield the case 4 and the upper cutter 10 to prevent a printed paper from entering the case 4 during a cutting operation.
The lower cutter 20 is attached to the printer body 1-2. More specifically, the lower cutter 20 is mounted at a predetermined position on a fixing member 2 such that the lower cutter 20 is partially overlapped with the upper cutter 10 while being in contact with the upper cutter 10.
In the conventional compact printer, the upper cover 1—1 is hingedly installed on the printer body 1-2. When the upper cover 1—1 is closed, the upper cutter 10 is partially overlapped with and engaged to the stationary lower cutter 20 fixed to the printer body 1-2. As the upper cutter 10 is laterally moved while being rotated, the upper cutter 10 gradually intersects with a cutting blade 20-1 of the lower cutter 20 to cut a printed paper disposed therebetween.
The lower cutter 20 is made of a metal plate of a predetermined thickness, and attached to the fixing member 2 separately mounted on the printer body 1-2. The rotary type upper cutter 10 intersects at its peripheral portion with the lower cutter 10 from side to side to sever a printed paper discharged therefrom at a predetermined length.
The upper cover is embodied into a clamshell shape and hingedly coupled to a side of the printer body by a hinge pin (not shown). When the upper cover is closed and locked to the printer body, the upper and lower cutters are disposed as shown in FIGS. 2 and 3.
FIG. 2 is a view showing an overlapped width “L1” of the upper and lower cutters before the upper cover is locked to the printer body, and FIG. 3 is a view showing an overlapped width “L2” of the upper and lower cutters when the upper cutter is fully locked to the printer body.
In the clamshell type upper cover, where a hinge point of the upper cover is set to be higher than the upper cover, a space required for opening and closing of the upper cutter is small, thereby causing replacement of a printing paper to be troublesome. On the contrary, where a hinge point of the upper cover is lower than the upper cutter, an overlapped width of the upper and lower cutters is not sufficient so that the upper cutter passes over the lower cutter.
On this account, in a clamshell type compact printer, an overlapped width of the upper and lower cutters 10 and 20 is closely related to a hinge point of the upper cover. Although it is preferable that an overlapped width of the upper and lower cutters is set to be “L1” as indicated in FIG. 2, the overlapped width “L2” must be accepted in the case of the clamshell type, in which a cover swings to be opened and closed. Hence, a contact surface between a printed paper and an upper cutter becomes large, causing quality of a cut paper to be deteriorated.
The upper cutter 10 is engaged with a cutting blade of the lower cutter 20 when the upper cover 1—1 is closed relative to the printer body 1-2. Then, as the upper cutter 10 is laterally moved while being rotated, its edge gradually intersects a cutting blade of the lower cutter 20 from side to side to cut a printed paper disposed therebetween.
Accordingly, an cutting blade of an upper surface of the lower cutter serving to cut a paper by cooperation of the upper cutter requires periodic maintenance for retaining its precision. That is, since the lower cutter is worn in its upper surface as a printer is used for a long time, cutting performance of the lower cutter is deteriorated according to degree of wear.
Such wear of the lower cutter may cause an outputted and discharged printing paper to have an irregularly cut line, and may cause a jam phenomenon at the cutting blade.
On this account, although the lower cutter must be precisely ground at an upper surface being in contact with the upper cutter, there is a limit to reduction of a thickness or a size of the lower cutter because of deformation due to a grinding or a heat treatment. In other words, it is further difficult to reduce an overall size of the lower cutter.
As a result, there is an economic drawback in that a used lower cutter must be frequently replaced with a new one.
When the upper cutter 10 is overlapped on the lower cutter 20, the upper cutter 10 is biased toward the lower cutter 20 by elastic means “S” inserted on a rotating shaft “H” between a carriage 3 and the upper cutter 10. A printed paper “P”, which is discharged from the printer, is cut by lateral movement of the upper cutter 10 as well as rotation of the upper cutter 10 caused by the driving gear “G”. A paper end under the cut line does not pass between the upper cutter and the lower cutter but is bent and penetrates under the upper cutter 10 when the paper is further discharged.
To this end, there is a necessity for assuring an ejecting path for a printing paper, thereby requiring another structure for defining an ejecting path. Therefore, there is a limit to reducing the upper cutter to a predetermined size or less.
The printing paper is supplied as a rolled paper, and is gradually reduced in its roll diameter during progress of printing. Owing to the small diameter of the rolled paper, the paper supplied from the rolled paper must be curled or curved, thereby causing a jam phenomenon of the curved paper.
When the upper cutter laterally moves from side to side relative the lower cutter to cut a printing paper, the shutter member 5 is swung about the hinge pin “h” to prevent a jam phenomenon of a printing paper. Therefore, there is also a limit to reducing an overall size of the cutting device due to an operating radius of the shutter member.